Machinery's Handbook, 31st Edition
BEARING DESIGN AND APPLICATIONS 2481 Tapered bore bearings are often used in applications such as these, again requiring care ful and well worked-out assembly procedures. They can be assembled on either tapered shafts or on adapter sleeves. Advancement of the inner race over the tapered shaft can be done either by controlled heating (to expand the race as required) or by the use of a hydrau lic jack. The adapter sleeve is supplied with a lock-nut which is used to advance the race on the tapered sleeve. With the heavier fits normally required to effect the clearance changes compatible with such mountings, hydraulic removal devices are normally recommended. For the conventional application, with standard fits, clearances provided in the standard bearing are suitable for normal operation. To insure that the design conditions are “nor mal,” a careful review of the application requirements, environments, operating speed range, anticipated abuses, and design parameters must be made. General Bearing Handling Precautions.— To insure that rolling element bearings are capable of achieving their design life and that they perform without objectionable noise, temperature rise, or shaft excursions, the following precautions are recommended: 1) Use the best bearing available for the application, consistent with the value of the application. Remember, the cost of the best bearing is generally small compared to the replacement costs of the rotating components that can be destroyed if a bearing fails or malfunctions. 2) If questions arise in designing the bearing application, seek out the assistance of the bearing manufacturer’s representative. 3) Handle bearings with care, keeping them in the sealed, original container until ready to use. 4) Follow the manufacturer’s instructions in handling and assembling the bearings. 5) Work with clean tools, clean dry hands, and in clean surroundings. 6) Do not wash or wipe bearings prior to installation unless special instructions or requirements have been established to do so. 7) Place unwrapped bearings on clean paper and keep them similarly covered until applied, if they cannot be kept in the original container. 8) Don’t use wooden mallets, brittle or chipped tools, or dirty fixtures and tools in mounting bearings. 9) Don’t spin uncleaned bearings, nor spin any bearing with an air blast. 10) Use care not to scratch or nick bearings. 11) Don’t strike or press on race flanges. 12) Use adapters for mounting which provide uniform steady pressure rather than ham mering on a drift or sleeve. 13) Insure that races are started onto shafts and into housings evenly so as to prevent cocking. 14) Inspect shafts and housings before mounting bearing to insure that proper fits will be maintained. 15) When removing bearings, clean housings, covers, and shafts before exposing the bearings. All dirt can be considered an abrasive, dangerous to the reuse of any rolling bearing.
16) Treat used bearings, which may be reused, as new ones. 17) Protect dismantled bearings from dirt and moisture. 18) Use clean, lint-free rags if bearings are wiped. 19) Wrap bearings in clean, oil-proof paper when not in use.
20) Use clean filtered, water-free Stoddard’s solvent or flushing oil to clean bearings. 21) In heating bearings for mounting onto shafts, follow manufacturer’s instructions. 22) In assembling bearings onto shafts never strike the outer race, or press on it to force the inner race. Apply the pressure on the inner race only. In dismantling follow the same precautions. 23) Do not press, strike, or otherwise force the seal or shield on factory-sealed bearings.
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